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4. INDIVIDUAL CANCERS 4.1 FEMALE BREAST CANCER
In 2003, there were 3738 female breast cancer cases that were reported, making it the most commonly diagnosed cancer in women. It accounted for 31.0 of newly diagnosed
female cases. Breast cancer was the commonest cancer in all ethnic groups and all age groups in females from the age of 15 years. The overall ASR was 46.2 per 100,000
population. The age pattern in 2003 showed a peak age specific incidence rate at the 50-59 age group
in Malays, Chinese, and Indians, and the rates then declined in the older age groups. Of the cases diagnosed in 2003, 64.1 were in women between 40 and 60 years of age.
Chinese had the highest incidence with an ASR of 59.7 per 100,000 population followed by Indian women with an ASR of 55.8 per 100,000 population and Malay women with an
ASR of 33.9 per 100,000 population. Compared to 2002 data, the ASR is lower for all races, but the age-specific incidence patterns are very similar.
4.2 LUNG CANCER A total of 1758 incident cases of lung cancer were reported, comprising 13.8 of male
cancers and 3.8 of female cancers. The male: female ratio in terms of incidence for Peninsular Malaysia was 2.8 : 1. Rates of lung cancer rose progressively with age for
both males and females. There was a steeper rise in incidence after the age of 40 years for both sexes, with a progressive divergence of the curves for the two sexes.
The incidence of lung cancer among the Chinese was higher than the other ethnic groups. The age-standardized incidence rate ASR, for Chinese was more than twice that of
Malays and Indians for both sexes. Even though lung cancer was in second place when colon and rectum were added
together, caution has to be exercised in its interpretation. This is because of : a the ascertainment rate calculated at 68 for 2002 data, and b comparing the age incidence
rate with reports from Singapore and Penang. We remind the reader that for this cancer, the registration was almost certainly
incomplete. The specific recruitment of radiologists and chest physicians to report cancers to the NCR from the middle of 2003 onwards, it is hoped that more complete
results will be available in the future.
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4.3 COLON AND RECTUM CANCER Cancers of the colon and rectum were recorded separately in this report. On their own
each of them ranked among the top ten most common cancers in Malaysia. When taken together, colorectal cancers would account for 14.2 of male cancers making it the
commonest cancer among men and the third most common cancer among women 10.1 of female cancers.
The male to female ratio for colon cancer was nearly equal 0.98:1, with the frequency in males rising more rapidly after the age of 60 years. In rectal cancer, the preponderance
of males was more noticeable 1.26:1, with a steeper rise in age specific incidence of males occurring at age of 50 years onwards.
The age specific incidence for both colon and rectal cancers increased exponentially with age. Chinese had a higher incidence of colon cancers than the other races. Comparing the
crude rates between Chinese and Malays, Chinese had more than 5.1 times the incidence of male colon cancer, and 4.6 times the incidence of female colon cancer. With regard to
rectal cancers, Chinese had the highest incidence rate of rectal cancers which was 2.8 times the Malay male incidence and 3.4 times the Malay females.
4.4 CERVICAL CANCER Cancer of the cervix was the second most common cancer among women. It constituted
12.9 of total female cancers. There were a total of 1,557 cases of cancer cervix, with an ASR of 19.7 per 100,000 population.
Cervical cancer incidence rate increased with age after 30 years. It has a peak incidence rate at ages 60 -69 years, and declined thereafter. These features were very similar to
data in 2002. Chinese women had the highest ASR of 28.8 per 100,000 population, followed by
Indians with ASR of 22.4 per 100,000 population and Malays with ASR of 10.5 per 100,000 population.
4.5 LEUKAEMIA A total of 539 cases of myeloid leukaemia and 433 cases of lymphatic leukaemia were